The proliferation of wireless devices in the recent past has been exceptional and includes communication and computing devices that are able to exchange data or voice signals amongst each other and/or with a central location. These devices communicate typically through radio waves over dedicated frequencies or dedicated segments of the electromagnetic spectrum. The range of these radio communications varies. For example, repeaters, cellular towers, or other nodes of the device's network may be used to extend that range. One example of these devices may be cellular telephones; however, other examples could include devices having multiple functions, such as portable or hand held computers with wireless capabilities, devices with e-mail sending and receiving capabilities, pagers, or two way radio communication devices.
The ability to estimate the relative distance between wireless nodes is becoming of upmost importance for a number of wireless device applications that require location awareness. Location awareness is also becoming important for asset tracking. As such, the need for Wi-Fi devices to provide location or positioning information is increasing For example, the United States Federal Communications Commission's E911 telecommunication initiatives require that wireless phone providers develop a way to locate any phone that makes a 911 emergency call. Location techniques will also be used for many future wireless systems and devices.
To support location services, a mobile station (STA) may negotiate with an access point (AP). The STA may send a request to the AP and the AP may respond with information enabling the STA to perform fine timing measurements. Wi-Fi based positioning system (WPS) is used where GPS is inadequate as in multipath and signal blockage indoors, among other things. An access point, which may be a Wi-Fi or WiMAX capable device, may exchange ranging signals with other access points or network devices. Ranging signals typically identify the transmitting device by a network address or other identifier and can be used to measure the time of flight between two wireless devices. Fine timing measurements may then be used to determine a round-trip time for signals exchanged by a pair of wireless devices. However, neither the STA nor the AP set conditions and/or preferences for the establishment of the fine timing measurement service.